A tritium diagnostic and trap for JUDITH—First results in disruption simulation experiments with neutron irradiated beryllium during cyclic electron beam testing

In the present study, the effect of disruptions on beryllium has been studied. Disruptions are simulated in the electron beam facility JUDITH by high energetic pulses of up to 250 MJ/m2. Under these loads, the beryllium surface may roughen combined with the forming of cracks. During the experiments, a special problem arises from the fact that during the neutron irradiation beryllium transmutes to tritium. This tritium is bound in the beryllium matrix, but during the heating of the samples, the tritium may be set free and through the vacuum pump it may be released to the environment. In order to avoid and to quantify this release of tritium, a special tritium trap has been constructed. In this tritium trap the gas is pumped by means of a metal bellows pump through a catalyst tube filled with copper oxide. At a temperature of 300 °C, the tritium is oxidized to HTO. This HTO is lead through gas washing bottles filled with water. Here approximately 98% of the released tritium is caught. The temperatures in the process are controlled by thermocouples, and the tritium content is controlled by a tritium gas monitor and in addition with a liquid scintillation counter (LSC).